iHD is an interactivity specification developed jointly by Microsoft and The Walt Disney Co. The XML-based interactive functionality provision is currently supported by the HD-DVD group and will be an integral part of Microsoft's upcoming Windows Vista operating system, expected to be released in late-2006. This support in Windows Vista is definite whether or not any next generation optical disc formats support it.
Supporters of iHD say that it will be less expensive for computer manufacturers since it is already part of Windows Vista. The alternative to iHD, Java-based BD-J, is supported by the Blu-Ray group. Since it appears iHD is more cost-effective implementation, Hewlett-Packard urged the Blu-ray Group to support iHD instead of BD-J, and implement one other feature - Mandatory Managed Copy.
HP is also negotiating with other Blu-ray supportive manufacturers but declined to say which (although you could probably guess if you looked at the Blu-ray supporters list. Besides HP, Apple and Dell are two other major manufacturers). Since iHD is XML-based, it is not exactly specific to optical discs, iHD content could be delivered solely over the Internet for example.
The main reason why computer manufacturers would prefer to see iHD support in Blu-ray as well as HD-DVD is the dominance of "Windows" in the operating systems market. Since iHD is included in Windows Vista, manufacturers would be paying for the interactive layer in the cost of the operating system, saving them from having to pay royalties for the Interactive layer. This makes an effective difference for PC manufacturers that ship millions of new PCs each year.
Ultimately it comes down to user experience however. HP believes however that iHD would benefit not only companies such as itself, but consumers also.
News History concerning iHD
HP urges Blu-Ray group to support more features
HP urged the Blu-ray group to support iHD and Mandatory Managed Copy, commenting that if in the end one format supported them and the other didn't, they would make a choice based on the difference.
Blu-Ray group responds to HP proposals
The Blu-ray Group responded to the proposals made by HP concerning iHD and Mandatory Managed Copy, saying that Mandatory Managed Copy would be included in the Blu-ray spec but that the group was still working with the Java-based solution (BD-J). The group said it would not allow iHD to delay the launch of the format.
This Glossary item will change as more details concerning iHD emerge.